Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona c/Martí i Franquès 1, 08028 Barcelona (Spain).
Angew Chem Int Ed Engl. 2014 Sep 22;53(39):10525-30. doi: 10.1002/anie.201402342. Epub 2014 Jun 11.
Platinum is the most versatile element in catalysis, but it is rare and its high price limits large-scale applications, for example in fuel-cell technology. Still, conventional catalysts use only a small fraction of the Pt content, that is, those atoms located at the catalyst's surface. To maximize the noble-metal efficiency, the precious metal should be atomically dispersed and exclusively located within the outermost surface layer of the material. Such atomically dispersed Pt surface species can indeed be prepared with exceptionally high stability. Using DFT calculations we identify a specific structural element, a ceria "nanopocket", which binds Pt(2+) so strongly that it withstands sintering and bulk diffusion. On model catalysts we experimentally confirm the theoretically predicted stability, and on real Pt-CeO2 nanocomposites showing high Pt efficiency in fuel-cell catalysis we also identify these anchoring sites.
铂是催化中用途最广泛的元素，但它很稀有，而且价格高昂，限制了其大规模应用，例如在燃料电池技术中。尽管如此，传统的催化剂仅使用了铂含量的一小部分，也就是说，那些位于催化剂表面的原子。为了最大限度地提高贵金属的效率，应该使贵金属原子分散并仅位于材料的最外层。确实可以使用异常高的稳定性来制备这样的原子分散的 Pt 表面物种。通过 DFT 计算，我们确定了一个特定的结构元素，即氧化铈“纳米袋”，它可以强烈地结合 Pt(2+)，从而使其能够承受烧结和体相扩散。在模型催化剂上，我们通过实验证实了理论预测的稳定性，并且在用于燃料电池催化的实际 Pt-CeO2 纳米复合材料中，我们也鉴定出了这些锚定位点。
